VOLVO
CEM-B104F17 - Switch Polling Pullup. General Electrical Failures. Circuit voltage above threshold
System
Central Electronic Module (CEM)
Volvo models this fault code applies to
Applies to the following models:
2 modelsV40 (2013–), V40 Cross Country (2013–)
Show models by year and engine (2)
What does this fault code mean?
The CEM keeps watch on a group of switches and contacts, including those for the doors, bonnet and brake lights. The fault is set when the CEM reads the signal as meaning that all of these have been active for too long. The code does not necessarily mean the CEM is faulty; it can also be set for other reasons.
Possible causes
- Internal fault in the CEM
- Insufficient battery voltage
What you can do
- 1Switch the ignition off and on once, then read off the codes again
- 2Check the battery charge and that the terminal clamps are tight and free from corrosion
- 3Check that the connectors to the doors, tailgate and brake lights are fully engaged and not damaged
- 4If you have a diagnostic tool, follow in live data how the status of the doors, tailgate and brake pedal changes when you open, close and press the brake
- 5If the code comes back and stays, have a workshop with diagnostic equipment check the central electronic module
Symptoms you may notice5
- The tailgate or trunk lid is hard to open
- Hazard warning lights do not work
- Passenger compartment lighting does not work
- Automatic engine start and stop does not work
- Tail lights or brake lights do not work
General guidance for car owners. Diagnosis on the car can point to a different cause.